The present invention generally relates to the field of information processing systems, and particularly to a system and method for processing audio information using optical processing techniques.
Voice encoders (VOCODERS) are utilized for processing audio information such as a speech signal. Such voice encoder systems are typically semiconductor based using semiconductor based digital electronic circuits for processing the audio information. Traditional semiconductor based digital electronic processors are typically serial devices processing data in a serial manner, i.e. a first operation is performed on a first set of data before a second set of data is fetched and operated upon. Although advents in semiconductor based processor architectures, such as predictive branching and higher processor speed, have provided processors capable of performing increasingly faster operations, the fundamental serial structure of semiconductor processing systems inherent in the device technology (e.g., von Neumann architecture) have limited the speed at which complex processing algorithms such as signal processing and compression may be performed with a general purpose semiconductor based processor. Further, although specialized semiconductor processors have been developed having architectures optimized for signal processing algorithms (e.g., digital signal processors, Harvard architecture), semiconductor devices still exhibit considerable signal processing limits. These problems become apparent when it is desired to process and transmit a voice or similar audio signal over a limited bandwidth transmission channel. VOCODER designs such as those utilized in the telephone industry function at the phonetic level with sounds and utterances such that a codebook or library of sounds by necessity is kept minimal in size (e.g., 512 phonemes). However, only smaller sized codebooks may be utilized since traditional semiconductor processors do not provide the necessary processing power to work with larger, massive sized codebooks. Increasing the size of the codebook would provide higher speech quality and lower bandwidth requirements, but at the expense of requiring significantly faster and more powerful sequential processors that may not exist, or may be too expensive or impractical for a given application. Lack of adequate processing power introduces processing latencies resulting in unacceptable speech quality and audio delay in the system.
Optical processing systems that utilize holographic image processing techniques are capable of processing information in parallel such that much more complex two-dimensional functions such as compression, correlation, and transform decomposition of audio time and frequency elements may be processed in a shorter amount of time than with traditional semiconductor processors. Such optically implemented signal processing functions may provide optimized transmission of speech signals over much lower bandwidth channels with much higher speech quality. For example, many voice encoders today have limits at or near 2.4 kilobits per second (kbps) (e.g. FED-STD-1016: CELP (4.8 kbps); FED-STD-1015: LPC-10e (2.4 kbps), ITUG.7231.1: CELP (5.3 and 6.3 kbps); IMBE (2.4 to 9.6 kbps), MPEG-4: Parametric (2 to 8 kbps), MIL-STD-118-113: CVSD (16 and 32 kbps)). Search for technology to dramatically reduce the required bandwidth for voice transmission is pressured by an entire industry of wired and wireless telecommunications companies seeking ways to offer more voice channels over limited numbers of communication channels or through constrained bandwidth. Thus, there lies a need for an audio processing, encoding, decoding and transmission system that utilizes optical processing to provide faster and more optimized transmission of audio signals such as speech signals over lower bandwidth transmission channels.
The present invention is directed to a system for processing and encoding audio information. In one embodiment, the system includes an audio transducer for receiving audio information and converting the audio information into a signal representative of the audio information, a digital processing system for receiving the signal and for electronically processing the audio signal, and an optical processing system operatively coupled with the digital processing system for performing a signal processing algorithm on the signal whereby the signal is encoded, the encoded signal being optimized for transmission over a lower bandwidth transmission channel.
The present invention is also directed to a method for processing and encoding audio information for transmission over a lower bandwidth channel. In one embodiment, the method includes steps for receiving the audio information and transducing the audio information into a signal representative of the audio information, electronically processing the signal, and optically processing the signal using an optical processing system such that the signal is encoded for optimal transmission over a lower bandwidth transmission channel. Both the method and the system of the present invention are capable of leveraging the enormous associative and correlating properties of an optical processing system that may occur in real-time with an extremely large, massive amount of data, making the optical processing system ideal for implementing simultaneous data correlation.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles of the invention.